CHATHAM — Glenwood Middle School in Chatham also was on “soft lockdown” for a time Thursday morning after an unspent shotgun shell was found outside the school.

Administrators called for the lockdown in coordination with the Ball-Chatham School District’s director of safety and security and local law enforcement so that the building and grounds could be searched, according to information that was posted on the school’s website.

No other shells were found, district spokeswoman Betsy Schroeder wrote in an email.

Two math classes will have to make up final exams Friday, Schroeder said.

The district has had at least two other lockdowns since last December. The middle school had a lockdown when a student found an empty bullet shell in a hallway three days after the deadly school shooting in Newtown, Conn.

Glenwood High School and neighboring Glenwood Elementary were put on lockdown Jan. 10 after a bullet was found in the parking lot of the high school.